In a conventional battery model identification method, in order to estimate SOC (State of Charge) of a battery, parameters of its battery model are identified based on frequency characters of the battery estimated using an alternating current impedance measurement method. (Refer to Patent Document 1 for example.)
Patent Document 1:
Japanese Patent Application Laid-Open Publication No. 2007-178215 (pages 2 to 17, especially the paragraphs [0069] to [0081], and all drawings)